The Big Bertha Diablo irons from Callaway are premium clubs with the better player in mind. They feature traditional head shapes, yet with Callaway's flaming Diablo cosmetics. The clubheads are forged from a soft 1020 carbon steel and feature high-strength 455 Carpenter Steel faces. The clubs are designed to provide exceptional feedback at impact thanks to the soft body, yet the stronger clubface should increase ball speed.